Apparatus for expanding sections of tubing



1933- E. RIEMENSCHNEIDER ET AL. 2,142,017

APPARATUS FOR EXPANDING SECTIONS OF TUBING Original Filed Fb. 27, 1932 faves 7 F/zMs/vscmvnaze Q Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE APPARATUS FOR EXPANDING SECTIONS OF TUBING Ernest Riemenschneider and Rudolph H. Thoms, Cleveland, Ohio, assignors to The Midland Steel Products Company, Cleveland, Ohio, a corporation of Ohio 10 Claims.

This invention relates to new and useful improvements in Apparatus for expanding sections of tubing and is a division of our co-pending application Serial No. 595,532 filed February 27, 1932, Patent Number 1,982,400, granted Nov. 27, 1934.

An important object of the invention resides in the provision of a pair of complementary axially movable dies having inter-fitting expander fingers adapted to engage the tubular stock at a plurality of points both circumferentially and longitudinally of the stock to expand and thicken a considerable section thereof and provide an enlarged or bulged annulus gradually tapering from its greatest diameter to the tubular stock.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawing forming a part of the description and wherein like numerals are employed to designate like parts of the several views,

Fig. 1 is a longitudinal vertical section through the tubular stock and one of the die members, the other member being indicated partly in elevation and with the dies in retracted position.

Fig. 2 is a similar view illustrating the position of the parts when the dies are in fully expanded positions.

Fig. 3 is a transverse section of the same taken on the line 3-3 of Fig. 2,

Fig. 4 is a miniature side elevation of the dies shown associated with the stock feeding arrangement, and,

Fig. 5 is a perspective View of the lower section of the die with the fingers spread to better illustrate the construction.

Referring now in detail to the drawing and for the purpose of illustrating one practical use of the apparatus, the treatment of stock for the formation of axle housings will be described, but it is to be understood that the apparatus herein disclosed is not to be limited in any respect to the precise article formed by the apparatus. Tubular welded or seamless stock of uniform diameter throughout is preferably used for the herein described method and is preferably stock having a wall thickness of T g of an inch and a diameter of approximately 3% inches which is approximately two inches less in diameter than that heretofore found necessary for the production of axle housings. This tubular stock is designated by the numeral 8 and has a uniformwall thickness throughout its entire length. The end of the tube to be expanded is preferably, but not necessarily heated to a proper forming heat. It is then slid down an inclined V-shaped trough 2 from an oven with its cool end leading downwardly to a second inclined trough 3, above which a lower'die member 5 is disposed in the inclined relationship shown in dotted lines in Fig. 4 in a position whereby the stock may be slid over the same with the hot end of the stock projecting beyond the upper end of the member 4 as shown in Fig. 1. The cylindrical body of the lower die is pivotally supported as at 6 on a horizontal axis so that it may be swung from the upright position shown in full lines in Fig. 4 to the inclined dotted line position for the reception of the tubular stock which is slid down the troughs 2 and 3. The die member may be pivotally supported in any suitable manner whereby it is absolutely stable in its upright position. Near the lower end of this pivoted die, the body is provided with an annular shoulder l for engagement with the lower cool end of the tubular stock.

The upper end 8 of this lower die terminates in a substantially tapered or conical nose having two degrees of taper 9 and H3 surfaced with stellite or any other suitable wear resisting material M. This double taper of the conical nose causes the expanded fingers of the complementary dies to take two different degrees of radial movement during the expanding operation, the .rst stage starting the fingers outwardly until the second stage takes effect and bears the brunt of the Work of guiding the metal of the stock outwardly as it is being bulged under axial compression.

t four equi-distant points circumferentially of the upper end of the lower die member 5, the tapered nose 8 and upper end of the body 5 are provided with longitudinally extending v-shaped grooves or recesses which open out into the periphery of the lower member for the retention of the inner ends of the four expander fingers l2. Pins l3 are extended through the body 5 and inner ends of the expander fingers to pivotally connect the latter to the lower die member. In their normal retracted or collapsed position, the inner longitudinal edges Id of the fingers abut the bottoms of the grooves or recesses so that the outer surfaces of the fingers conform to the shape of the body 5 and are substantially flush with the exterior surface thereof whereby the tubular stock may be freely slid over the lower die member and fingers. In cross section, the expanded fingers I2 are substantially triangular or sector shape, with their outer longitudinal surfaces l6 curved transversely to conform to the inner periphery of the tubular stock when the fingers are in collapsed position. These outer surfaces of the fingers l2 and outer ends are curved inwardly as at I! to provide the surfaces with cam like portions I8 adapted for engagement with the inner periphery of the tubular stock when the fingers are moved to expanded position. The forward ends of the fingers are inclined and lined with stellite IE! or other suitable wear resisting material for engagement with a tapered nose 20 provided on the upper die member.

This upper die member 20 is of substantially the same construction as the lower die member, especially as concerns its tapered nose portion and its four expander fingers 2| which are pivotally connected to the body of the upper member by means of the pins 22. The four expander fingers 2| of the upper die members are of the same construction as the fingers l8 of the lower mem ber and are arranged so that their free ends will ride between the fingers I2 of the lower die member when the two dies are moved toward each other. In this manner, the fingers of each die member slide between pairs of fingers of the other die member and are simultaneously moved radially outwardly as the upper die member 23 carried by a ram is moved axially into the tube and toward the lower die member. As the upper die member approaches the lower member,the inclined ends of the expander fingers of both members engage the tapered surfaces 9 of the complementary die members and are given a starting radial movement while at the same time the tubular stock is subjected to axial compression by reason of the lower end of the tube engaging the annular shoulder I of the lower die and the upper end of the tube engaging an annular shoulder 24 carried by the upper die. As the two die members move toward one another, the inclined portions IQ of all eight fingers ride upon the second inclined surfaces H] of the conical noses of complementary die members to effect a more gradual outward movement of the fingers to properly guide the metal of the tube to cause a considerable section thereof to be bulged outwardly and formed into an expanded annulus. The degree of expansion and the wall thickness of the expanded annulus and adjacent end of the tube may be controlled and varied within a wide range. depending upon the degree to which the stock is heated and the proportionate arrangement between the fingers and the abutments l1 and 24 whereby the axial compression of the tube may be properly co-related to the outward radial movement of the fingers. It will thus be obvious that the thickness of the metal in this end of the tube is controlled to the desired degree while the metal is being guided by the fingers outwardly to form a bulged annulus having a diameter in considerable excess of the original tube. Thus the wall thickness may be maintained the same as the original stock or slightly increased thereover by co-relating the axial and radial movements of the expander. Due to the radial movement of these eight fingers and their consequent wider spacing the farther out they go in the expanding movement, the bulged or expanded portion of the tube is formed to the cross section shown in Fig. 3 with the slight substantially elliptical shaped bulges or humps 26 formed by the cam portions l8 of the fingers contacting with the inside of the tube and these bulges are spaced both circumferentially and longitudinally of the tube due to the fact that the cams of the expander fingers of the two die members engage the tube at spaced points longitudinally thereof as more clearly seen in Fig. 2. In actual practice the metal in the hills of the bulges 26 may be rather thinned out while the metal in the valleys is thickened. As these undulations are slight they are smoothed out and brought to uniform thickness in subsequent forming operations.

As the plunger of the ram moves outwardly or away from the die member 5, the upper die member with its fingers 2| are moved outwardly from the expanded upset end of the tube, it being appreciated that the cam surfaces 18 of the fingers 2i ride upon the inclined walls on the expanded tube and are thereby moved inwardly to their normal position so as to be freely withdrawn from the upper end of the tube. By reason of the tapered nose 20 of the upper die member moving away from the free ends of the fingers I2 of the lower member, these fingers are free to move radially inwardly, whereby the tube I can be freely slipped off of the lower die member. This is accomplished by swinging the lower die member 5 to the dotted line position shown in Fig. 4 where the tube is withdrawn and another piece of tubular stock is inserted therein. After positioning the tubular stock on the lower die member, it is swung to the upright position shown in full lines at Fig. 4 in position to receive the upper die member as it descends to carry out the expanding operation above described.

It is to be understood that various changes in the shape and relationship of the various parts may be made without departing from the scope of the appended claims.

We claim:

1. An expander comprising a pair of complementary relatively movable dies each having expander fingers adapted to engage the other complementary die for moving the fingers of both dies outwardly into engagement with the work, the fingers of each die interfitting with the fingers of the other die and said fingers being returned to unexpanded position by engagement with the work during retraction of the work therefrom.

2. An expander comprising a pair of complementary relatively movable dies having adjacent ends provided with wedged surfaces, a plurality of expander fingers mounted on each die, the fingers of the two dies being arranged in interfitting relation and the fingers of each die being adapted to operate between the fingers of the other die and to engage the wedge surface of the other die for simultaneously moving the fingers of both dies outwardly into engagement with the work, upon relative movement of the dies.

3. An expander comprising a pair of complementary relatively movable dies having adjacent ends provided with somewhat conical noses, a plurality of expander fingers pivotally mounted at their inner ends to extend lengthwise in their respective dies and with their outer ends extending beyond the nose of their respective die, the fingers of the two dies being arranged in interfitting relation and adapted to engage the conical nose of the complementary die upon relative movement of the dies.

4. An expander comprising a pair of complementary dies, one of said dies being pivotally mounted and movable into axial alignment with the other die, one of the dies being movablc axially of the other, and one of said dies having expander means adapted to be operated by the other when the latter is moved axially.

5. An expander comprising a pair of complementary dies, one of said dies being pivotally mounted and movable to an upright operative position from an inclined one, the other die being movable axially of the upright position of the first die and one of said dies having expander means adapted to be operated by the other when the dies are moved relatively axially.

6. Means for expanding a hollow article comprising a pair of complementary relatively movable dies, each die having a tapered nose provided with circumferentially spaced recesses, a metal forming finger mounted in each recess and having a surface for engagement with the tapered nose of the other complementary die between a pair of fingers thereof to be moved thereby into engagement with the article.

7. Means for expanding a hollow article comprising a pair of complementary axially movable dies, each die having a tapered nose provided with a plurality of longitudinally extending circumferentially spaced recesses, a metal forming finger mounted in each recess and having an end extending beyond said nose, each finger having a surface inclined in a direction opposite to the inclination of the nose in which it is mounted to engage the tapered nose of the other complementary die between a pair of fingers thereof to be moved thereby into engagement with the article.

8. Means for expanding a hollow article comprising a pair of complementary axially movable dies, each die having a tapered nose and a plurality of metal working fingers connected thereto with corresponding ends projecting beyond the nose and formed to conjointly form a cavity into which the nose of the complementary die enters to engage the fingers and move them outwardly into engagement with the article upon axial relative movement of the dies toward one another.

9. Means for expanding a hollow article comprising a pair of complementary relatively movable mountings, metal forming fingers pivotally connected to each mounting with their ends projecting longitudinally beyond the end of the mounting and adapted to operate between the fingers of the other mounting to contact with the article for expanding the same, and each mounting having means adapted to engage said projecting ends of the fingers of the complementary mounting to move the fingers of the complementary mounting into engagement with the article.

10. An expander comprising a pair of relatively axially movable members each having expander fingers adapted to engage the other complementary member for moving the fingers of both members outwardly into engagement with the work, and the fingers of each member operating between the fingers of the other member.

ERNEST RIEMENSCHNEIDER. RUDOLPH H. THOMS. 

